"So, Andross! You show your true form!"
— Fox McCloud, Star Fox 64
"You are the first to see this form! Die! With my highest praise!"
— Nyarlathotep, Persona 2 Eternal Punishment
Roxas: One wing? Don't they just fly around in circles?
Axel: You know, they should, but they don't. No idea how that works.
— Organization LIX, "Rules"
"By slaying me in my true form, you have merely given me the power to assume my actual true form, which I'm about to do. Right now."
"No more clowning around. I'm not the Vindicator or the Victimizer or the Vaporizer or the Vibrator! I'm...THE VIOLATOR!"
—Clown from Spawn
"I am the lucid dream... The monster in your nightmares... The Fiend of a Thousand Faces! Cower before my true form! BOW DOWN BEFORE THE GOD OF DEATH!!"
"Now shall you deal with me, O Prince...and all the powers of HELL!"
— Maleficent, Sleeping Beauty
"The caterpillar sees not its destiny, except by fulfilling it. Only by shedding our previous bodies can we become beautiful butterflies. I see you have no wings. Let me show you mine."
*whooom* *whooom* *whooom* *whooom*
"You're in for it now. My second form makes the one you're familiar with look as gentle as a sleeping kitten."
— Freeza (who still has two more forms), Dragon Ball Kai
"A snake, am I? Perhaps you would like to see how ssssssssnake-like I can beeeee!"
— Jafar, before turning into a giant cobra, Aladdin
"Playtime's over. Grant me POWEEEEEERRRRRRRRRRR!!!!"
— Dracula assuming his demon form, Castlevania: Symphony of the Night
"I've avoided showing you this form! You'll wish you never crossed Veran, Sorceress of Shadows!"
— Veran, Zelda: Oracle of Ages
Death: My power! Use my power!
Dracula: Soul Steal! (merges with Death to become True Dracula)
"Say what you wish. I would become the Devil himself in order to protect Iris."
— Michael Zeppelin before fighting Grolla, RosenkreuzStilette
"I am the Devil...!" or "Grant me power...!"
— Michael Zeppelin assuming his demon form, RosenkreuzStilette
"You pompous maggot...! I shall show you the limits of a commoner!"
— Iris before the final battle in Rosenkreuzstilette Grollschwert, RosenkreuzStilette
Lord Krom Wrath: You're pathetic, Urkor Malravenus, hiding in that teddy-bear skin.
Deady: You have no sense of style, do you, Krom Wrath? But if you want to see me in my true form... you got it. (pulls off his teddy-bear head and turns into a giant tentacled skull with light-purple-pupiled eyes) Urkor Malravenus is here!
Lord Krom Wrath: Hmmm. I forgot how large you are.
Tahu: But... you are but a Tohunga!
Makuta: You expected something else? Something like... THIS!?
— BIONICLE: Mata Nui Online
"Ancient Spirits of evil, transform this decayed form to Mumm-Ra, the Ever-Living!"
— Mumm-Ra before transforming into his true form in ThunderCats
"Everyone, keep your guards up. That wasn't his full power. We can expect at least three levels of transformations, with additional power multipliers every time!"
— Valvatorez, Disgaea 4 This turns out to be an aversion.
Travis: *kicks Jasper's Pizza Batt Man form out the window* And that's a wrap!
Henry: No. Not yet.
* Jasper turns into a cartoony parade float and appears out the window*
Henry: Now that's hideous!
Travis: Rich assassins pull the craziest shit.
Hakuoro: I haven't told you yet, have I? About my real name.
Hakuoro: ...name is-!
*Hakuoro turns into Witsarnemitea*
Witsarnemitea: At this time, I shall cut away our accursed destiny!
Dii: I see. But you should know we cannot be killed no matter what!
*Dii responds in kind*
"HAHAGHAHGJAHGJHJAHHGAJSHJGHSAJAHSJGHASIGSA I AM GOD" [HP is 999999999999999999999999999999999999999999999999]
—Main Bad Guy, Every Single JRPG in History by Ghettoblasters
"THIS ISN'T EVEN MY FINAL FORM"
I've always heard about people having a conniption, but I'd never seen one. You don't want to see them. My wife's face... Split. The skin and hair split, and came off of her face, so there was nothing except a skull. An orange light came out of her hair; and lit all 'round. Fire shot from her eye-sockets..."